Carriage control for typewriters and the like



Aug. 30, 1949. F. BECKER CARRIAGE CONTROL FOR TYPEWRITERS AND THE LIKEFiled Dec. 30, 1946 IN VEN TOR.

FRED BECKER 2M 47%? ATTORNEY Patented Aug. 30, 1949 STAT ES FreedBecker, QueensaVill &&;.-N. Ya, assignon to? Underwaod.0orporationporation ofjDelaware Application December 30, 11746, SeriivDNm 719}1585. Claims (Cl. 191-82);-

ihis invention relates to typewriting machines and the like, and moreparticularly topawlr-andratchet devices associated with the carriagelettor-feed mechanism and operative incident to returnof the carriage.

An object of theinvention is to provide, in. a carriage-controlmechanism; an improved ratcheting device by which overloankingof thecarriage upon returning it to start a new line of typing is obviated.

In typewriters of certain construction wherein the. margin-regulatinmechanism is at the front of the frame-like carriage and the letterteedmechanism. with: its carriage-carried rack is adjacent the rear of thecarriage, there-is chance of overbanking occurring, particularlywhen-the carriage is returned manually with undue force or in powercarriage-retunr machines; This overbanking is-due in partto the.inherent-yieldab le character of the carriage frame and to a backlash ofthe mechanisms involved in banisingthe carriage at the left hand,orline-start margin; In conventional mechanisms the.- actual overbankingresults from the pawlvand'vratchet deviceassociatedwith the letter-feedmechanism ratcheting a letter-feed step beyond that determined by themargin regulator, so that after bankin the carriage at the leftmargin,when the letter-feed escapement resumes control: of the carriage, adiscrepancy of one letter spacein the line-start position of thecarriage iszhadh The present invention obviates this fault by providinga ratchet mechanismlin which thefpawl ma follow along with-ther-atchetwheel: or pinion an angular distance substantially greater thanthe pitch of the ratchet teeth, withoutratcheting intoa succeedingtooth. This enables the ratchet Wheel or pinion to-rotate,ifor instance,an angular distance equivalent to,. say, one and a third letter spaces,during the instant inwhich banking occurs; without the associated pawlratcheting into a succeeding tooth. Thus the ratcheting device willmaintain thesame interrelation between the carriage and letter-teedmechanism and will accommodate an appreciable over-travel of thecarriage rack induced by the springing of the carriage frame and thetaking up of backlash in the carriage-arresting parts.

Other objects of the invention are. inpart obvious and in partparticularly pointed out asthe 2 proved; paw-l: andiratchet: device,themechanism amhdevicc beinggills the quiescent condition: withthe-:carriage-at restlimpositionto start a new line ysllin ztFigureflziaaiviewvsimilar too-Figure 1:but howing the parts-ohthe-feedmechanism; and ratchet device-inztiiepositions Whichthey maytake at the instant: the; carriage ishanked; at; the line.- starton-lefthandim'argin, thairis; just after the return of: the; oamiage:iSi terminated; and

Figures 3: is: a diagrammatic; plan. view ofa th l: ynewriter carriage.showing: in. dot-and.- dashputline,somewhatexag erated, the yield; ofthe: carria e: incident; to; this banking.

Theinvention; is: advantageous.- paitticularly in its: operativerelation: with the; IBJJLQFfGGd meek..- anism; oi thetypewriten; Thismechanism may be; of} any, well-known kind and? operates, to advance:the: panensupporting: carriage; one letterspacecsteptincident to; the;typing of each characten-ofrthetyping line: When the typedline iscompleted the carriage isreturned; Figure: 3, either" manually orbypower; to the line-start position as determined by the engagement of acoun-tcrstop; 5, onthe; carriage 6 with; an? adjust,- ably:positionable-margin. stcp- T: on the typewriter main frame.

Apart from: the improved ratchet device; of the invention,- the:letter-feed escapement mechanism illustrated is 0t conventionalconstruction, a: briefi description Qt which follows.

A- toothed rock 8; is mounted on the carriage and meshes withan1escapement pinion 9 which aismserves ao a ratchet wheel; thesemembers 8 and: a comprising an operative connection betweem thecarriage6; and an escapement mechanism M). This mechanism includes mainly anescapement wheel: M with which a pivoted stepping dog: Lland a detent,dog 13; cooperate in the usual. mannerto control the letter-feed stepsof thecarniiaga The carriage 6, is actuated; in the direction of thearrow in Figure l by the usual carriage springdrum, not shown; Thefeeddogs 1-21, 7 3 are-mounted on a dog rocker M rockable pivots l-5iThe dog rocker is actuated by the type actions; oi the; typewriterthrough a universa1- ban nottshowni, to the dog rocker rear- Wendi-y. Aspring l6: connected to the stepping dog t2 tends to pull; this dogrightward towarda stop 11- andis-biased so; as to. also restore the dogM to its forward, inactive position. The pinion or ratchet it andytheescapemen-t Wheel H aremblmted:to rotate-independently on a stud l8secured to a. frame 210.- wh-ich. also mounts the pivots I5. The tensionon the Car iage spring drum, tending to move the carriage rack 8leftwardly and to rotate the pinion 9 counterclockwise, is transmittedfrom pinion 9 to the escapement wheel H by a novel ratchet pawl 22,hereinafter described. The teeth of the escapement wheel I I are beveledas shown and the detent dog l3 has its leading edge beveled on the'farside. As the dog rocker l4 rocks rearwardly the detent dog I3 engagesthe same tooth of wheel II that was engaged by the stepping dog l2, thebevels on dog l3 and the escapement wheel teeth facilitatin thisengagement. As dog l2 leaves the wheel tooth, spring [6 swings this dogleftward against stop ll so that dog [2 is in a position to engage thenext tooth of wheel II. This occurs incident to the type actionrestoring, the dog rocker l4, therefore, returning to its'forwardposition. As detent dog l3 leaves the wheel tooth and dog l2 assumesengagement with the next tooth, the tendency of the carriage to moveleftward causes the escapement wheel H to rotate until dog [2, cominginto engagement with a stop not shown, arrests wheel il in the positionshown in Fig ure 1. Each letter-feed step of the carriage, includingword spaces, is effected by a similar operation of the escapementmechanism.

Upon completion of a line of typing the carriage is returned to theline-start position as determined by the left-hand margin stops 5, 1.Before the carriage begins to return, the escapement mechanism andratchet device are in the condition shown in Figure 1. As the carriageis moved in the return direction indicated by the arrow in Figure 2, thecorresponding movement of the rack 8 rotates pinion 9 clockwise and thisrotation, transmitted to the escapement wheel ll via the tensionedratchetpawl 22, rotates the escapemen-t wheel ll slightly in acounter-feed direction until a back-check dog 23 mounted on the rocker Mis engaged b the immediately preceding tooth of wheel II. This check dog23 is urged leftwardly by a spring 24- to rest against a stop 25, thespring yielding to permit the check dog 23 to swing rightwardly and thusratchet idly over each tooth of the escapement wheel during theletter-feed action. As the carriage continues its return travel the pawl22 ratchets over each tooth of the pinion 9 until the return of thecarriage is terminated at the line-start margin.

Pawl 22 is mounted on the escapement wheel I I in such manner as to becapable preferably of both pivotal and endwise or linear movement. Astud 27 secured to wheel I l projects from the face thereof into a slot28 in the pawl, the slot extending substantially lengthwise of the pawl.A

spring 33 wound about a pin 3| on wheel H, has one end anchored in thewheel and has the other end pressing against the end of the pawl 22opposite its slotted end, a groove in the pawl receiving the curved endof the spring. A cam pin 32 secured to wheel ll coacts with a cam 33formed on pawl 22. The shape of the cam face 33 is such as to guide thepawl in a generally endwise or linear movement as generated by theaction of the pawl tooth 22' as the pinion 9 turns clockwise and thepawl tooth follows along to a predetermined extent without ratcheting.The two positions taken by the pawl 22 at the start and at theconclusion of this follow-up action are shown in Figures 1 and 2,respectively. This motion of pawl 22, against the tension of spring 33,is taken while a straight or nearly straight intermediate portion of cam33 rides along pin 32, and is terminated by an angular face or shoulder34 of the cam coming against the pin. At the 4 other end, the cam facemay take a slight turn from the straight portion, as indicated at 35,which acts to cam the pawl tooth 22' into the tooth space of pinion 9.Spring 30 is arranged so as to exert a pressure generally endwise of thepawl, tending to move the pawl, by coaction of cam 33, to the positionof Figure l. The contour of the effective portion of cam 33 may bevaried somewhat from that shown, it being noted that the function ofthis cam is to cause the pawl tooth 22' to seat positively into thetooth space of pinion 9 when no ratcheting takes place as duringletter-feeding, and to cause the pawl tooth to move along with the samepinion tooth to a certain extent of, say, one and one-third times atooth pitch or letter space without ratcheting.

The extent of follow-up movement of pawl 22 may be modif ed to suitvarious conditions in the typewriter. It is, however, desirable to limitthis movement to a maximum of, say, one and a fraction letter-spaces asthe back-spacing mechanism of the typewriter should operate to backspacethe carriage to a corresponding extent. It may be here noted that thetooth pitch of pinion 9 is such that there is one tooth for each letterspace or, in other words, if the letter spacing is ten per inch, thereare ten tooth-spaces in pinion 9 for each inch of carriage travel.

The operating efiect of the pawl-and-ratchet device in obviatingoverbanking will now be described. It will be noted that at the start ofcarriage return .the escapement mechanism assumes the condition shown inFigure 2 but pawl 22 has not as yet moved relatively to wheel H and itstooth 22 is still engaged between the two teeth of pinion 9. It will befurther noted that the escapement wheel II has rotated clockwise aslight degree from the Figure 1 position, as indicated by the rightwarddisplacement of the dotted arrow on rack B from arrow 36 in Figure 2,and that pawl 22 has moved bodily with wheel I I. As the carriagecontinues to be returned pinion 9 now turns while wheel ll remainsstationary, being held by check-dog 23. After pinion 9 has -turned alittle more than, say, one and a third tooth spaces, during whichrotation pawl 22 has moved along with the pinion, the endwise movementof pawl 22 is stopped by shoulder 34 and the pawl ratchets into the nexttooth space. This ratcheting action occurs once for each letterspacedistance of carriage return and until the carriage is stopped by themargin stops 5, 1. If the carriage were to be brought up lightly to theline-start position so that the margin stops 5, 1 just contactedlightly, the escapement mechanism l i would be as shown in Figure 2 butthe pawl 22 would nevertheless be in its inactive position as inFigure 1. To clarify the description, the

position of slight advance of the escapement wheel H which it assumesduring carriage return, may be disregarded except to note that the pointof engagement of the margin stops 5, l is such as to allow for thisslight advance, and that after carriage return the carriage settles backa corresponding extent as the escapement mechanism, particularly thefeed dog [2, resumes |c0n- I 2, i3, 23 are in the Figure 2 position butthe pawl tooth 22' is still in the position of engagement with pinion 9as shown in Figure 1. This relation of pinion 9 and wheel H is indicatedgraphically by the two arrows 31 in Figure 1 being aligned with eachother. As the forceful banking of the carriage occurs, with the tendencyof overbanking as indicated by the dot-anddash outline of the carriagein Figure 3, the rack 8 moves rightwardly to an extent such as thatindicated by the rightmost or solid arrow on rack 8 in Figure 2. Thisextent of course varies somewhat in accordance with the force of impactat the instant of banking the carriage, but for the purposes of thisdescription it may be assumed to be about one and one-third letterspaces. The corresponding displacement of pinion 9 relatively to wheel1! is shown by the displacement of the two arrows 36 in Figure 2. Thetooth of pinion 9 with which pawl tooth 22' had been engaged before thetendency to overbank occurred is marked with a cross in Figures 1 and.2. During this rotation of pinion 9, the pawl tooth 22' has moved outfrom the tooth space of pinion 9 and pawl 22 has advanced bodily withthe pinion, so that notwithstanding the advance of pinion 9 to an extentgreater than a tooth space, the pawl has not ratcheted into the nexttooth space. Instead, at the end of the overbanking action, the pawltooth 22 is still in such position that it will reengage in the sametooth space of pinion S that it engaged when the margin stops 5, Icontacted lightly. In other words, the same letter space relationbetween the carriage 6 and the escapement mechanism I is maintainednotwithstanding that the carriage rack 8 has overtraveled an appreciabledegree beyond that at which the stops 5, I determine the line-startposition. From this it will be seen that after the carriage has beenfully banked and the rack 8 settles back to its normal relation with themargin stops, the pinion 9 will recede to a position in which the arrows3! are again aligned and the pawl tooth 22 will again seat into thepinion tooth space with which it was previously engaged. During thisrecessive action, pawl 22. under the camming action assisted by spring3|], retards from the Figure 2 position to the Figure 1 posit on as thearrows 3! move toward registry with each other. Meanwhile rack 8 hasbeen restored to its position indicated by the dotted arrow. Followingthis the carriage settles to its normal letterfeed pos tion asescapement wheel I l resumes its Figure 1 position to again come undercontrol of the feed dog I2 as the escapement mechanism resumes controlof the carriage position.

Although in this applicat on, there is specifically described one embodment which the invention may assume in practice, it will be understoodthat the invention may be modified and embod ed in various other formswithout departing from its spirit or the scope of the appended claims.

What is claimed as new is:

1. In a typewriter or like machine, the combination with a carriageletter-feed escapement mechanism having dogs cooperating with a toothedescapement member to control the letterfeed steps, of a one-way drivedevice interposed between the carriage and the escapement mechanism andeffective to enable return of the carriage without a ratcheting actionof the escapement mechanism, said device including a toothed ratchet anda pawl and mounting means therefor having provision for limited movementof the pawl in a direction generally along the line of the ratchet toothtravel occurring incident to returning the carriage.

2. In a typewriter or like machine, the combination with a carriageletter-feed mechanism having dogs cooperative with a toothed escapementmember to control the letter-feed steps, of a pawl-and-ratchet deviceinterposed between the carriage and the letter-feed mechanism andeffective to enable return of the carriage without a ratcheting actionof the letter-feed mechanism, said device including a pawl and mountingmeans therefor providing for pivotal movement and lineal movement of thepawl, the latter to an extent greater than the pitch of the ratchetteeth.

3. In a carriage control for typewriters and the like having aletter-feed escapement, a line-start margin device and an operativeconnection between the carrlage and the escapement including aratcheting device operative incident to returning the carriage to theline-start position, said ratcheting device comprising a pawl andmounting means therefor having provision for pivotal movement and linearendwise movement of the pawl to an extent greater than a step of letterfeed.

4. In a carriage control for typewriters and the like having aletter-feed mechanism and a linestart margin device, the letter-feedmechanism including an escapement wheel and a back-check dog, anoperative connection between the carriage and escapement wheel includinga toothed ratchet coaxial with the escapement wheel, a springpressedpawl cooperating with said ratchet, and means mounting said pawl on theescapement wheel for limited movement relatively to said wheel and inthe general direction of rotation of the ratchet teeth taken incident toreturning the carriage to the line-start position determined by themargin device.

5. In a carriage control for typewriters and the like having aletter-feed mechanism and a linestart margin device, the letter-feedmechanism including an escapement wheel and a back-check dog, anoperative connection between the carriage and escapement wheel includinga toothed ratchet coaxial with said escapement wheel, a springpressedpawl cooperating with said ratchet, a pin-and-slot connection mountingsaid pawl on the escapement wheel, and a cam-and-follower device betweensaid pawl and wheel, said connection and said cam device coacting tocause said pawl to follow along with the ratchet teeth to a limitedextent during rotation of the ratchet incident to returning the carriageto the linestart position.

FRED BECKER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 472,870 Ford Apr. 12, 18921,123,463 Anderson Jan. 5, 1915 2,385,035 Smathers Sept. 18, 1945

